Why are Lawnmowers so Much Louder than Normal Consumer Vehicles?

Do you have neighbours? If you do, you’ve probably been in the situation at least once where on a Sunday morning, you are roused from peaceful slumber by the incessant gnawing of a lawnmower. You lie in bed forcing your eyes to stay shut in a feeble attempt to fall back to sleep even though you know it won’t happen. You might lie there thinking “Why on a Sunday morning, Bill?” and old Bill seems oblivious to his crime.

The next question that probably pops up then, is why on Earth are lawnmowers so much louder than regular cars? They’re much smaller than regular cars. They don’t get up to any kind of real speed like cars. They don’t have to carry heavy loads like cars. So why are they so loud?

Let’s investigate:

There are a few very simple reasons why lawnmowers are as loud as they are, even though they are typically only around the 3rd of the size of an average car engine. Would you have thought a comparatively tiny engine could be so much noisier than its larger counterpart? It’s quite baffling!

Here are some of the reasons why this is:

  • Like cars, most lawnmowers have internal combustion engines. Internal combustion engines are, at a base, very loud. They work by a system of pistons being moved by built up pressure and heat being released as a result of burning some kind of fuel. These movements are essentially miniscule explosions happening inside the engine, so you can see why it would be a noisy process!
  • Even though car engines tend to work in similar ways, car engines are fitted with specifically engineered mufflers which work to dampen and soften the noise made by the engine. Lawnmowers don’t generally have the same muffler system, so you are getting the full force of the engine noise, rather than a tamed version. Sadly, it is much cheaper to produce lawnmowers without mufflers so this is unlikely to change unless people become willing to spend a lot more on their grass-cutting apparatus!
  • The size of cars also contributes. There is a lot of buffering and padding (for lack of better terms) surrounding a car engine, but with lawnmowers, the engine is much more exposed to the outside world, and as such, the sound is allowed to travel more freely. Maybe we need to invest in gigantic car-like lawnmowers!
  • As you will most likely know, cars have complicated and effective exhaust systems which contribute to lessening the impact of engine noise. Lawnmowers do not have as complex and efficient exhaust systems. Unfortunate, isn’t it?
  • Most lawnmowers (although not all) do not have water cooling systems like cars do. Cooling the engine relieves the extreme pressure and subsequently lessens the volume of engines. Lawnmowers that do have water cooling systems are generally not as loud as others. If this tickles your fancy, it might be worth looking into.
  • Rubber vibration dampers can be fitted to lawnmowers and they drastically reduce engine noise. However, these miraculous-seeming parts are not suitable for very grassy and uneven terrain such as that lawnmowers are often used on. It seems like just as we come close to finding a solution, it is ripped away from us!
  • One of the biggest factors contributing to how loud lawnmowers are has nothing to do with the engine at all. Would you believe that one of the biggest noise sources is actually the movement of the lawnmower’s blades whipping around cutting through plant material? Well, take my word for it. The repeated revolutions make a surprising amount of noise and can be very loud.
  • Electric mowers are generally quieter, not having the hassle of an internal combustion engine to deal with. If you’re looking for a subtler mowing experience, then an electric lawnmower might be the perfect solution for you!

Hopefully, this has shed some light on exactly why Bill makes so much noise with his mower. Unfortunately, there is not all that much that can be done but having a better understanding of why lawnmowers are so loud at all can only help! Next time you’re woken up by an eager neighbour, maybe your thought process will change to “Why can’t he have an electric mower?”.

Maybe one day, lawnmower manufacturers will find a way of creating a ninja mower that makes little to no noise and can be used at all hours of the day, no matter how obscene. But until then, we have what we have and must make do.

One important thing to stress when mowing your garden is to ALWAYS wear eye and ear protection. Mowing can be a messy business with bits of grass, soil, and even small stones being flicked all over the place. Wear eye protection and make sure none of these things gets flicked into your eye. Prolonged or frequent mowing without ear protection can damage your hearing irreversibly so take the necessary action to safeguard yourself against this.

(Maybe earplugs are the solution for Sunday mornings when Bill mows his grass?)


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